Don't skip the amps. Those Polks want, and need the power. There is nothing wrong with what you have chosen, and, I would bet money that it would probably smoke any system owned by the people telling you that receiver has enough power. People using mid-fi receiver power don't know the difference. If they did, they wouldn't be using receiver power.
zumbo, we see a lot of things alike. However,
per usual we are
all responding without information that might be necessary yet unsupplied by the OP. I really believe that this need is greatly dependent on many things such as:
-the size of room
-distance from speakers
-speakers' efficiency
-speakers' load
-normal volumes desired
-full range speakers, if not, at what x-over
As with you, my separate amp gives me
so much better audio in terms of dynamic range, volume without distortion, less compression, etc. Things do sound better for such reasons. However, I run 6 of 7 speakers as full range, have decent distance from the speakers, on average the speakers have tough loads, I like it loud, etc...
Someone in a 12x12 room, who only enjoys moderate volumes, and x-overs all the speakers at 80hz, while having 93db efficiency at 8 ohms, etc, only 5-6 ft from speakers, etc, will be plenty fine with that 905. Still, I agree with you zumbo in the general principle that many people have no idea what they are missing. But definitely
not all.
Lastly, I have an audiophile friend who I respect greatly who once owned the Lsi series bookshelves. I haven't asked what he thought of them. I know after I heard the lsi25 towers, my opinion is that they are
easily the most veiled speaker of 25-30 pairs I've heard at over the 1k mark. However, they were powered with a Pioneer Elite receiver, perhaps not nearly enough current to open them up. I immediately recoginzed the Vifa ring tweeters (seen them before on other speakers, maybe Audio Physic?), and the dealer didn't even know... Anyways, there was a thread at AVS, with a former dealer speaking, and he said that Polk really inflates these Lsi msrp prices so that the discounts look all that more enticing.
I personally hate the Lsi speakers. I would easily pay less and get something else. I have never heard the Rti line, but I have heard Polk's cheapest selections... and lastly, thanks for all the info on the Quarts, zumbo, much obliged.
regarding the veiled nature of the Lsi... the Quad 22L was pretty veiled too. Still, even if the Lsi seemed a lot worse, it was not an A/B test, and the Quads had the benefit of hi-current Rotel power.